A trick ignition system born in race car engines is bringing high-efficiency superpowers to a Mopar near you, no hybrid batteries required. Starting in the 2026 Jeep Grand Cherokee and gradually replacing the aging 3.6-liter Pentastar V6 before it, Mopar’s next mass-market mainstream engine is called the Hurricane 4 Turbo. Among its numerous tricks, it incorporates a multi-flame blowtorch to light its fuel / air mixture, giving engineers an entire new universe of control over the combustion process that has major and timely implications for your wallet.
Like the mass-market switch to Gasoline Direct Injection (GDI) and turbocharged engines in the 2000s and wider rollout of hybrid tech in the decades that followed, the pre-chamber ignition system represents another major technological shift. The combustion engine is far from dead these days, and technologies like Turbulent Jet Ignition (TJI) are demonstrating that gas-burning engines still have remaining efficiency waiting to be unlocked, with or without hybrid assist.
TJI From The Racetrack To The Driver’s Seat
Maserati Nettuno V6Maserati
Gasoline engines have been around for well over a century, and for most of that time, they all ignited their air-fuel mixture in the same way: with a spark plug. As engines advanced to become lighter, better breathing, more efficient, and more durable, the spark plug was always the star of the show. Some engines evolved to use two spark plugs instead of one, but spark-ignited gas engines from economy to exotic all had the lowly spark plug in common.
2026 Jeep Grand Cherokee extrior in brown frontStellantis
Around the mid 2000s, engineers building racing engines needed a major efficiency boost to meet regulatory targets, and the pre-chamber ignition system started to make its way into the most cutting-edge engines mankind was building. The technology proliferated through racing engines, and entered the Stellantis gene pool by way of the Maserati MC20 supercar, and specifically, its twin-turbo V6 “Nettuno” engine which ran the same pre-chamber ignition concept found in various racing engines of the day.
As the latest engineering often does, this trickle-down tech from the world of racing would one day benefit customer and automaker alike with more power, lower emissions, and reduced fuel consumption.
Model
Pentastar V6
Hurricane Turbo 4
Engine
3.6-Liter Pentastar V-6 (launched 2011, WK2 Grand Cherokee)
2.0-Liter Hurricane Turbo 4 (launched 2026, 2026 Grand Cherokee)
Type & Description
60-degree V-type, liquid-cooled
Inline 4-cyl, turbocharged, liquid-cooled
Bore × Stroke
3.78 × 3.27 in
3.31 × 3.54 in
Compression Ratio
11.3:1
12.0:1
Power
293 hp @ 6,400 rpm
324 hp @ 6,000 rpm
Torque
260 lb-ft @ 4,000 rpm
332 lb-ft @ 3,000–4,500 rpm
Max Engine Speed
6,700 rpm (limited)
6,500 rpm (limited)
Transmission
8-speed automatic
8-speed automatic
EPA Annual Fuel Cost
$2,850
$2,850
Assembly Plant
Saltillo South Engine Plant, Mexico
Dundee Engine Plant, Michigan
In 2020, during an interview with Autoline Network, Mike Bunce, head of research for Mahle Powertrain North America, described the company’s work with the F1 endeavors of various manufacturers. These included Ferrari, which won races with an engine using the early “Mahle Jet Ignition” (MJI) system that preceded mainstream applications. It’s the ultimate proving ground, a rapid technology accelerator for us,” Bunce explained on the brand’s involvement with F1 engine development.
Using Flame Jets For A Cooler Running Engine
New Hurricane 4 TJI Cylinder Head Close UpStellantis
Alright gearheads, here’s the sticky on TJI. Think of the anatomy of a standard four-cylinder turbo engine, and you’re most of the way there. Each combustion chamber in the Hurricane 4 Turbo engine has two intake valves (fed by an upstream fuel injector), two exhaust valves, and a spark plug.
From this basis, the Hurricane 4 Turbo TJI engine adds a component to the cylinder head, fitting each combustion chamber with the combustion pre-chamber. This is a press-fit copper dome about the size of a pencil eraser. Inside, an additional fuel injector and spark plug are contained. They’re separated from the combustion chamber by the copper dome, which, by the way, has a ring of tiny little holes around it.
2026 Jeep Grand Cherokee extrior in brown rear quarterStellantis
The pre-chamber is positioned in the center of the combustion chamber ceiling, between the valves, where the conventional spark plug normally resides. In a TJI engine, the conventional spark plug remains present, it’s just moved off to the side. Notably, the pre-chamber system in the Maserati Nettuno V6 engine was about the size of an actual spark plug, while the Hurricane 4’s pre-chamber has been downsized considerably for the first modern, mass-market application.
If you’re counting, that means each cylinder within the Hurricane 4 Turbo engine has four valves, a port fuel injector upstream, a conventional spark plug, and the TJI pre-chamber opening, with an additional fuel injector and spark plug inside.
Jeep Hurricane 4 Turbo EngineJeep
When activated by the engine computer, the pre-chamber fills with fuel that’s ignited by the spark plug within. This causes jets of fire to blast out of the pre-chamber’s 360-degree array of holes, igniting the waiting fuel and air in the “main” combustion chamber not with a tiny spark, but with multiple jets of fire that cover the roof of the cylinder head instead. This combusts the main-chamber air-fuel mix more thoroughly and rapidly than spark alone, and helps the engine work at 12.0:1 compression and over 40 percent thermal efficiency.
“Imagine taking a spark plug and placing it anywhere you like inside the combustion chamber, anywhere in space,” said Bunce. “Then imagine multiplying it, so you can have six or seven or eight of them. That’s essentially how this concept works, but instead of spark plugs, we’re using these very fast-moving jets to accomplish the same thing.”
The resulting numbers are particularly impressive: with the Variable Geometry Turbocharger spinning up 35 pounds of boost, the TJI system takes this 2-liter engine to 324 horsepower and 332 lb-ft of torque. That’s 26% more power density than the Hellcat Redeye V8 (162 hp per liter), if you’re counting. It’s also 20% more power from 10% less fuel than the outgoing 2.0-liter engine, or an advantage of 31 hp and 72 lb-ft of torque over the Pentastar V6, which drinks the same amount of your fuel dollars annually, according to EPA data.
The Long Road To Mainstream
2025 Maserati MC20 CieloMaserati
Readers may recall the fascinating history of the Cadillac Magnetic Ride control system, which took seven years to go from test mule validation to its first mass-market application in 2002. Inventing and perfecting the technology was one battle, setting it up for affordable mass adaptation was an entirely different one. That’s why cutting-edge tech often exists in niche or racing applications for years before it winds up in your Hellcat or Corvette or Viper or Jeep Grand Cherokee.
In the case of pre-chamber ignition, the industry began researching development in the mid-2000s, before years of bench testing ahead of motorsport validation around the mid 2010s. In his 2020 interview with Autoline, Bunce says that both passive and active pre-chamber systems were in development. In 2026, the TJI-equipped Hurricane 4 Turbo arrived in the Jeep Grand Cherokee for the first time.
TJI Is A Timely Technology That Could Help Engine Parts Last Longer
grand cherokee trailhawkJeep
Stellantis isn’t the only automaker bringing pre-chamber ignition engines to market, and even the latest BMW M3’s straight-six engine has adopted a version of the technology to help meet stricter regulatory targets coming for the 2027 model year.
maserati mc20 engineMaserati
In that application, BMW references the pre-chamber system as a means of delivering more efficiency across more situations, better fuel consumption rates at full throttle, enhanced durability, improved cold-start performance and no power sacrifice as key advantages. Importantly, pre-chamber ignition allows automakers to maintain the performance of their combustion engines while meaningfully reducing emissions and consumption without the need to add heavy hybrid tech to the mix.
As Stellantis moves away from plug-in-powered vehicles, the timely launch of TJI technology gives shoppers expected fuel savings and emissions improvements without electrification. It’s the sort of non-electrified, power-boosting solution that Mopar shoppers like.
“The Hurricane 4 might not be replacing the 3.6 just yet, but more models will likely start to join in on the fun. Anything that currently uses the V6 (save for the Ram 1500) is up for discussion, but the Maserati V6-derived engineering leads us to wonder what the performance applications are for this little 4-cylinder. The upcoming Dodge GLH, which harkens back to Carroll Shelby’s work on the Omni GLH (slang for “goes like hell”), is more than likely where we’ll see the first performance application of this engine in one of Stellantis’ mainstream brands. The Hurricane 4 wasn’t built for the gas-hungry V8 enthusiasts, nor was it made to replace the beloved 3.6 from the outset. It was built to prove the 4-cylinder engine could be the sweet spot that combines economy with power in the modern era without any mention of the word ‘hybrid’.” – James Kelly, CarBuzz writer
With fuel prices remaining unstable, we see another bit of timeliness dialed into the new engine: its ability to deliver premium-grade power density on regular-grade gas is sure to be an advantage in the marketplace.
Remember: this engine is the new mainstream powerplant designed for everyday consumers and fleet operators, not an exotic one-off. Even more impressive than the power-per-liter leap is the fact that the Hurricane 4 Turbo engine makes advertised figures on regular-grade 87 octane fuel, not the pricey high-grade almost universally required by engines that make 162 hp per liter. Turns out, the pre-chamber system itself actually makes the use of high-octane fuel obsolete in this application.
“You end up with very fast, very complete combustion,” explained Bunce. “This lets us ignite mixtures that wouldn’t normally be very ignitable with a spark plug alone. We’re operating with a significant excess of air now, which normally a spark plug couldn’t ignite.”
2027 Jeep Grand CherokeeJeep
There’s also the thermal efficiency, reaching a whopping 40.5 percent. Even in 2020 during development, early pre-chamber systems were showing major advantages to combustion temperatures. This could have yet-untold effects on long-term durability, even as internet comment sections fill with speculation about the new engine’s reliability, with some commenters wondering if this high-boost, complex new engine will be failure-prone.
Anything’s possible when you make things up, but as explained by Bunce, “temperatures that the bodies of the engines are exposed to are much lower. In a typical gas engine, a lot of fuel energy is lost to heat. We’re cutting that by half. The engine is much cooler.” With temperatures down, durability improves, turbochargers have an easier life, and various engine parts and processes can be re-engineered and optimized since they no longer need to deal with as much thermal stress.
Base Trim Engine
Pentastar 3.6L ICE
Base Trim Transmission
TorqueFlite 8-speed automatic
Base Trim Drivetrain
Rear-Wheel Drive
Base Trim Horsepower
293 HP @6400 RPM
Base Trim Torque
257 lb.-ft. @ 4000 RPM
Base Trim Fuel Economy (city/highway/combined)
19/26/22 MPG
Base Trim Battery Type
Lead acid battery
Sources: Stellantis, EPA, Mahle, Autoline Network
